A simulation can be used to provide representations of certain characteristics or behaviors of a particular physical or abstract system. For example, simulations can be used to show the effects of particular courses of action. A physical simulation is a simulation in which physical objects are substituted for a real thing or entity. Physical simulations are often used in interactive simulations involving a human operator for educational and/or training purposes. For example, mannequin patient simulators are used in the healthcare field, flight simulators and driving simulators are used in various industries, and tank simulators may be used in military training.
Physical simulations can provide tactile and haptic feedback for a human operator and a three-dimensional (3-D) interaction perspective suited for learning psycho-motor and spatial skills.
For example, in the health care industry, medical simulators are used to teach therapeutic and diagnostic procedures, medical concepts, and decision making skills. Many medical simulators involve a computer or processor connected to a physical representation of a patient, also referred to as a mannequin patient simulator (MPS). These MPSs have been widely adopted and consist of an instrumented anatomical model that can sense certain interventions and, via mathematical models of physiology and pharmacology, the model reacts appropriately in real time.
For example, upon sensing an intervention such as administration of a drug, the model can react by producing an increased palpable pulse at the radial and carotid arteries and displaying an increased heart rate on a physiological monitor. In certain cases, real medical instruments and devices can be used with the life-size MPSs and proper technique and mechanics can be learned.
Physical simulations or objects are limited by the viewpoint of the user. In particular, physical objects such as anesthesia machines (in a medical simulation) and car engines (in a vehicle simulation) and physical simulators such as MPSs (in a medical simulation) remain a black-box to learners in the sense that the internal structure, functions and processes that connect the input (cause) to the output (effect) are not made explicit. Unlike a user's point of reference in an aircraft simulator where the user is inside looking out, the user's point of reference in, for example, a mannequin patient simulator is from the outside looking in any direction at any object, but not from within the object. In addition, many visual cues such as a patient's skin turning cyanotic (blue) from lack of oxygen are difficult to simulate. These effects are often represented by creative substitutes such as blue make-up and oatmeal vomit. However, in addition to making a mess, physically simulated blood gushing from a simulated wound or vomit can potentially cause short-circuits because of the electronics in a MPS.
Virtual simulations have also been used for education and training. Typically, the simulation model is instantiated via a display such as computer, PDA or cell phone screens, or stereoscopic, 3-D, holographic or panoramic displays. An intermediary device, often a mouse, joystick, or Wii™, is needed to interact with the simulation.
Virtual abstract simulations, such as transparent reality simulations of anesthesia machines and medical equipment or drug dissemination during spinal anesthesia, emphasize internal structure, functions and processes of a simulated system. Gases, fluids and substances that are usually invisible or hidden can be made visible or even color-coded and their flow and propagation can be visualized within the system. However, in a virtual simulation without the use of haptic gloves, the simulator cannot be directly touched like a physical simulation. In the virtual simulations, direct interaction using one's hands or real instruments such as laryngoscopes or a wrench is also difficult to simulate. For example, it can be difficult to simulate a direct interaction such as turning an oxygen flowmeter knob or opening a spare oxygen cylinder in the back of the anesthesia machine.
Tactile and haptic feedback are also missing from virtual abstract simulations. In addition, the resulting virtual simulation may be abstracted to the point that it is significantly different from the actual physical layout of the real system. This abstract representation can present challenges when transferring what was learned to the actual physical system. In addition, existing virtual environment systems tend to be unwieldy, bulky, and expensive.
Computer monitor-based graphics or video based simulations are easier to distribute, but can lack in-context integration. Video based simulations can provide abstract knowledge, but can be limited in the ability to connect the abstract to the physical.
Augmented reality consists of computer generated virtual objects that have been integrated into the user's experience of the real world so that the virtual objects appear real. This alignment represents one of the core technical difficulties in augmented reality, and has many applications. For example, consider a medical training simulation scenario in which users need a high degree of visual realism of the patient and haptic feedback when they touch it. A virtual patient can exhibit high visual realism, but it must be aligned or registered with a physical mannequin, which provides haptic feedback.
Accordingly, there is a need for a simulation system that addresses the shortcomings noted in existing systems.